The invention relates to an arrangement for separating adjacent packages that are conveyed in and out of the arrangement by transport elements. The packages are conveyed into the separating arrangement in a random, adjacent arrangement; a preprocessing system ensures that no packages lie on top of others. The term packages also encompasses parcels, newspaper bundles and sack-type mail items. After the separating process, the packages are conveyed consecutively to a further processing system. This can be the input part of a sorting system in which the packages are sorted according to various criteria (e.g., recipient address, color or size).
EP 780 328 A1 discloses a corresponding separating device having consecutive sections with driven rollers that are oriented at a diagonal with respect to a guide wall. The roller speeds increase from section to section in order to create spaces between the packages. The transport path for the packages thereby becomes narrower from section to section, so only individual packages leave the device. The packages that are separated out via the open sides in the sections travel back to the transport path with the sections by way of a return path. This solution requires a large amount of space, particularly with respect to length, and does not assure reliable separation of packages of different sizes, because two narrow packages can pass through the separator side by side.
U.S. Pat. No. 5,638,938 describes a further separating device for packages, in which a plurality of separately-driven, ascending transport belts are disposed one behind the other, with the packages falling from the upper part of the preceding belt onto the lower part of the next belt. Light barriers are disposed between the belts. If packages are located within a light barrier, the drive of the respective preceding belt is shut off. This pulls apart the bunch of packages in the transport direction. Because it is also possible, however, for packages to be adjacent to one another, fingers are provided for only allowing the passage of one package out of a plurality of adjacent packages. The fingers are controlled by the signals of an optical sensor line disposed transversely to the transport direction. This solution also requires a considerable structural length, and also does not assure reliable functioning with packages that vary widely in size (particularly with the use of the fingers).
It is therefore the object of the invention to create the most compact possible arrangement for separating adjacent packages, whose function is not affected by the size of the packages.
Because of the array-type arrangement of lifting mechanisms, between which transport belts are located, and the purposeful actuation of the lifting mechanisms and the drive within the described time frames on the basis of the detected packages, the design can be very compact, and packages of varying sizes can be separated reliably, with the intervals of the lifting mechanisms being selected to ensure that packages of a fixed minimum size are reliably separated.
In one embodiment, lifting magnets were selected as an advantageous embodiment for the lifting mechanisms. When the packages are conveyed in, the tappets of the lifting magnets are located in the upper end position, and after the incoming phase has ended, an adjusting mechanism raises all of the lifting magnets, or lowers the transport belts such that the tappets are located above the transport plane of the transport belts. When the first package is separated out, all of the tappets on which no packages are located are additionally lowered, and after the separation process, the adjusting mechanism lowers the lifting magnets again, or the transport belts are raised again and all of the tappets of the lifting magnets are moved back into the upper end position. The raising and lowering of all of the lifting magnets, or the lowering and lifting of the transport belts by an adjusting mechanism, allows the tappets of the lifting magnets to be moved into the upper end position without a load. Because only a small retaining current is necessary for holding the tappets in the upper position, even with a load, the current requirement for the lifting magnets can be kept low. Pneumatic or hydraulic lifting cylinders can be used as an advantageous embodiment of the lifting mechanisms. When the packages are conveyed in, the tappets of the lifting cylinders are located in the lower end position, and after the incoming phase has ended, the tappets of the lifting cylinders above which packages are located are moved into the upper end position above the transport plane of the transport belts. This advantageous embodiment does not require a central adjustment of the lifting cylinders or transport belts, because their tappets can also be moved upward under a load.
It is advantageous to damp the downward movement of the tappets, so the contact with the packages is not lost during the downward movement of the tappets, and the packages are extensively prevented from sliding. With the lifting magnets, this damping can be attained by means of induction or an eddy current, and with the lifting cylinders, by way of additional valves. Measuring elements, which additionally record the height profile, are advantageously also provided for reliably identifying packages that are touching. These measurements can be performed with, for example, laser trio regulation.
In a further advantageous embodiment, a color-recording device, which is used in conjunction with or in place of the measuring elements that record the occupied surfaces, is provided for better identification of packages that are touching.
In the advantageous embodiment, an optical sensor line is provided transversely to the transport direction, and beneath the transport plane, for determining the base shapes of the packages in front of the transport belts and lifting mechanisms. Because the packages are transported past the sensor line, an interval-setting device is used for easily determining the occupied surfaces for the traversed path and the control device.
The occupied surfaces/base shapes can also be ascertained simply and reliably if the lifting mechanisms are equipped with sensors that detect the tappet load as of a minimum weight.
When it is necessary to orient the packages, it is also advantageous to lower the tappets that are beneath a fixed point of rotation later than the other tappets under the respective package, so the transport belts rotate the packages about this point during this time.